The purpose of this investigation is to test the hypothesis that antibiotics are involved in maintenance of dormancy and timing of germination of spores of the organism producing them. Spores of Streptomyces viridochromogenes release a substance during germination which inhibits germination of fresh spores of the organism. The germination inhibitor is also an antibiotic. The germination inhibitor will be identified and its location in spores and mechanism of inhibition determined. The mechanism of release of the inhibitor during germination will also be determined. Spores of other species of Streptomyces are being screened to determine if they also release germination inhibitors. Effort will be concentrated on aminoglycoside producing organisms because of the highly sensitive tests available for detecting the antibiotics. Properties of spores of non-antibiotic producing mutants will be compared to the wild type. The properties tested will be extent of dormancy, germinability and presence of germination inhibitors.